Medical institutions are equipped with a radiation tomography apparatus that allows imaging of radiopharmaceutical distribution as described in, for example, Patent Literature 1. Description will be given of a detailed construction of such a radiation tomography apparatus. The conventional radiation tomography apparatus includes a radiation ring having radiation detectors arranged circularly for detecting radiation. The detector ring detects a pair of radiation (an annihilation radiation-pair) having opposite directions to each other that is emitted from radiopharmaceutical within a subject.
A type of such the radiation tomography apparatus includes a radiation tomography apparatus for breast inspections. Description will be given in detail of the radiation tomography apparatus for breast inspections. FIG. 8 illustrates a conventional radiographic apparatus for breast inspections. A conventional radiographic apparatus 51 for breast inspections guides one breast of a subject into a detector ring 62. The detector ring 62 detects annihilation radiation-pairs emitted from the subject under this condition.
The detector ring 62 identifies generating sources of the annihilation radiation-pairs emitted from the breast, thereby generating radiopharmaceutical distribution in accordance with positional information on the generating sources. The more radiopharmaceutical is likely to be accumulated in cancerous tissue rather than normal tissue. Consequently, checking the radiopharmaceutical distribution allows diagnosis for breast cancer.
A diagnosing method is to be described in detail. Firstly, a breast of a subject is set in a radiation tomography apparatus. Secondary, detection of an annihilation radiation-pair starts. The annihilation radiation-pair is continuously detected until a satisfactory number of beams of annihilation radiation for image generation is detected. When a satisfactory number of beams of annihilation radiation is obtained, detection of the annihilation radiation-pair is completed. Then, a tomographic image having the breast of the subject appearing therein is generated in accordance with the accumulated detection data.